[Hilo] What’s the difference of the <AT+CSQ> during a call or out of call? Why sometimes RSSI of +CSQ changes much, while Rx level of <AT+KCELL> changes few?
Answer: While in Idle mode (no call), Signal strength value returned by AT+CSQ is based on BCCH Rx level.
While in Dedicated mode (during call), Signal strength value returned by AT+CSQ is based on TCH Rx level.
Usually TCH channel are broadcasted at lower power than BCCH channel (as BCCH is first channel that is listened to by MS to locate a cell).
AT+KCELL report is always based on BCCH channel of serving cell.